Benzodiazepines (BZs) and related drugs commonly are prescribed for treating anxiety and sleep disorders. Their clinical utility is based on their behavioral effects which are attributed to positive allosteric modulation of the GABA-A receptor. Multiple subtypes of the GABAA receptor exist, and recent research has focused on understanding the role of BZ-sensitive GABAA receptors (i.e., receptors containing alpha-1, alpha-2, alpha-3, and alpha-5 protein subunits) in the behavioral effects of BZ-type drugs. Results from a body of work suggests that the anxiolytic or anti-anxiety effects of BZ-like drugs likely involve alpha-2- and/or alpha-3-containing GABAA receptors, while their sedative-like effects are attributable to alpha-1GABAA receptors.